With the development of the Long Term Evolution (LTE) system, the use of Machine Type Communication (MTC) has been gradually increased. Therefore, it is foreseeable that the number of user equipment (UEs) served by one base station will also be continuously increased in the future. In the related art, a Physical Random Access Channel (PRACH) access mechanism is as follows: a UE transmits PRACH preambles on a PRACH resource, which occupy time-frequency resources including one subframe in time domain and 6 resource blocks (RBs) in frequency domain. It can be seen in FIG. 1 that the PRACH access method in the related art provides a limited number of PRACH access serial numbers. As the number of UEs served by one base station increases hugely, access collisions are certain to increase, causing a great increase in a probability of multiple access retransmissions or even access failures.